Echidna



Echidna is a giant, flying, snake demon that both Nero and Dante fight. In snake form, she resembles a giant snake with a few feathery frills around the neck and multiple eyes on the head being the only diference between it's and a regular snake's appearance. However, the head "unzips" in four places down the head and this reveals Echidna as a humanoid female with glowing eyes and no lower body (or it is at least inside the snake portion) with a pair of red plumes on her head that combine to form the tounge of the snake. She appears to be able to generate eggs of some sort and eject them from pores on the body. Dante (in regular fashion) responds by kicking a bunch of them into the forest she is hovering over, which all ricochet off the trees in a complex manner that leads them to hit her. She then tries to eat Dante, but Dante forces his way out of her mouth and fights her. In the end she is killed by Dante, who then uses the newly acquired Devil Arm, Gilgamesh to destroy her Hell Gate.

Chimera
A Chimera Seed is a demon sired by Echidna that attempts to lunge at its opponents but more often they try to infest other demons, like Scarecrows or Assaults, to become a Chimera. When Chimeras are made they become deadly bladed enemies who viciously assault their enemies. They however only move at the speed of their hosts natural body and while they are a bit more resitant to damage, overall they attack more. Keep them from entering other demons and take them out quickly.

Background
Echidna was the mother of many monsters in Greek mythology, including Cerberus. This explains her laying the seed-like eggs, as they were her children.